\begin{table}[htbp]\centering
\def\sym#1{\ifmmode^{#1}\else\(^{#1}\)\fi}
\caption{Electoral System, Candidate Communication, and Change in Partisan Affect (Traits)\label{tab:aptcon}}
\begin{tabular}{l*{3}{c}}
\hline\hline
                &\multicolumn{1}{c}{(1)}   &\multicolumn{1}{c}{(2)}   &\multicolumn{1}{c}{(3)}   \\
                &Affective Polarization   & In-Group   &Out-Group   \\
                &     b/se   &     b/se   &     b/se   \\
\hline
RCV Compliment  &    0.003   &    0.005   &   -0.000   \\
                &  (0.003)   &  (0.004)   &  (0.004)   \\
RCV Comp. + Endorse&   -0.001   &   -0.001   &    0.001   \\
                &  (0.003)   &  (0.004)   &  (0.004)   \\
Age             &    0.000   &   -0.000   &   -0.000   \\
                &  (0.000)   &  (0.000)   &  (0.000)   \\
Female          &   -0.001   &   -0.000   &    0.001   \\
                &  (0.002)   &  (0.003)   &  (0.003)   \\
Education       &    0.002*  &    0.002   &   -0.003*  \\
                &  (0.001)   &  (0.001)   &  (0.001)   \\
White           &   -0.005*  &   -0.003   &    0.008   \\
                &  (0.003)   &  (0.004)   &  (0.004)   \\
Liberal         &   -0.067***&   -0.058***&    0.076***\\
                &  (0.005)   &  (0.008)   &  (0.008)   \\
Moderate        &    0.005   &    0.005   &   -0.006   \\
                &  (0.010)   &  (0.016)   &  (0.015)   \\
Demcorat        &    0.002   &    0.011   &    0.007   \\
                &  (0.008)   &  (0.012)   &  (0.012)   \\
Republican      &    0.013   &   -0.002   &   -0.028*  \\
                &  (0.009)   &  (0.013)   &  (0.013)   \\
Constant        &    0.012   &    0.030*  &    0.007   \\
                &  (0.010)   &  (0.015)   &  (0.014)   \\
\hline
R$^2$           &     0.35   &     0.08   &     0.32   \\
\textit{N}      &     2250   &     2250   &     2250   \\
\hline\hline
\end{tabular}
\end{table}
